XXV 



ON IONS WHICH ARE CAPABLE OF CALLING FORTH 

 RHYTHMICAL CONTRACTIONS IN SKELETAL 

 MUSCLE 1 



1. IN 1881 Biedermann published a remarkable observa- 

 tion "On Rhythmical Contractions Brought about in Striated 

 Muscle through Chemical Stimulation." 2 The observation 

 consists, according to his description, in the following: 



The sartorius of a frog, previously poisoned with curare, is 

 carefully removed from the body, if possible at a low temperature 

 (0 to 10 C.). If now the muscle preparation fastened vertically 

 into a muscle clamp, and weighted by its femoral stump, is dipped 

 into a 0.6 per cent, sodium-chloride solution .... containing 

 some ordinary alkaline, crystallized sodium phosphate, besides a 

 small amount of sodium carbonate (in the liter of distilled water 

 were contained 5 g. NaCl, 2 g. Na 2 HPO 4 , and 0.4 to 0.5 g. Na 2 CO 3 ), 

 which must be kept at a low temperature (3 to 10 C.), one observes 

 as a rule, after a longer or shorter period of rest, that the immersed 

 muscle begins to beat rhythmically. 



The twitchings vary in intensity. At times we have to do 

 with a mere tremor; at times, however, powerful beats and 

 contortions of the muscle occur; sometimes only individual 

 fibers are active; sometimes the whole muscle is involved. 

 Finally, the process may be limited to certain portions of 

 the muscle ; at other times the whole muscle may be involved. 

 At low temperatures these phenomena may continue for 

 days. 



Biedermann recognizes the importance of this observa- 

 tion for the decision of the question whether the heart muscle 

 is of itself capable of rhythmical activity without the inter- 

 vention of the ganglion cells. 



1 Festschrift fur Professor Fick (Braunschweig, 1899), p. 101. 

 *Sitzungsberichte der Wiener Akademie, Vol. LXXXII, Part III (1880). 



518 



